Do extension tubes work with a macro lens

[ilzho]

Hello:

Do extension tubes help a macro lens gain further magnification or do they only help non macro lenses?

I have a 100mm macro lens and love it, but am curious to know if extension tubes would help it.

Thank you.

[Waddizzle · Accepted solution]

Extension tubes do not care what type of lens you are using.  Using an extension tube may get you higher magnification, but there are unexpected traps to be aware of.  An extension reduces the Minimum Focusing Distance, MFD, of a lens.

Thanks to the laws of physics, if you move a lens little bit further away from the sensor, you lose the ability to focus at infinity, but you also gain the ability focus closer to an object, or subject.  Extension tubes come in different sizes, rated in millimeters.

With most conventional lenses, you want to use an extension tube, or a stacked combination of extension tube that is roughly 25-33% of the focal length of the lens you are using.  The longer the length of your extension tube, the closer you can get to a subject, which is not always a good thing.

It is possible to add too much extension tube distance, such that the maximum focusing distance is so close to the image sensor, that MFD is actually inside of the lens body!  This is why you do not want to use too much focal length.  The problem is also the primitive

[ilzho]

Thank you...

Great information.

[ebiggs1]

A true macro lens will be sharper, more versatile, and easier to handle than any of the add-ons either on the front of the lens or behind it.  With extension tubes you lose f-stop(s) and flash becomes quite difficult.  Especially as the front of the lens to subject decreases. This can be over come but the lost of IQ can not. Invest in a true macro lens. You'll be much happier.

[ilzho]

Thank you,

I do have the 100mm f2.8 L macro lens and love it.

Just curious to know if an extension tube would help get closer...

[ebiggs1]

+1 

[diverhank]

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@ebiggs1 wrote:

A true macro lens will be sharper, more versatile, and easier to handle than any of the add-ons either on the front of the lens or behind it.  With extension tubes you lose f-stop(s) and flash becomes quite difficult.  Especially as the front of the lens to subject decreases. This can be over come but the lost of IQ can not. Invest in a true macro lens. You'll be much happier.

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I maybe wrong but as far as I know, you don't lose f/stops with an extension tube and you don't lose IQ either.  You are probably thinking about teleconverters.  An extension tube has no lens component and simply adds distance between the lens and the sensor.  The drawbacks are as described by Waddizle.

[AndyMilnePhotog]

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@diverhank wrote:

I maybe wrong but as far as I know, you don't lose f/stops with an extension tube and you don't lose IQ either.  You are probably thinking about teleconverters.  An extension tube has no lens component and simply adds distance between the lens and the sensor.  The drawbacks are as described by Waddizle.

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I disagree. What Ernie was saying is that extension tubes cause a loss of light regardless of the lens used. As for IQ goes, IQ drops slightly because the lens' optical flaws are magnified (i.e softness in the corners, increase in chromatic abberation, etc.).

Canon cameras do not report the exif data regarding the actual f/stop or should I say light transmission. Therefore, with all macro lenses and extension tubes in general, the closer you focus on your subject, the more light is lost as a result.

[diverhank]

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@AndyMilnePhotog wrote:

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@diverhank wrote:

I maybe wrong but as far as I know, you don't lose f/stops with an extension tube and you don't lose IQ either.  You are probably thinking about teleconverters.  An extension tube has no lens component and simply adds distance between the lens and the sensor.  The drawbacks are as described by Waddizle.

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I disagree. What Ernie was saying is that extension tubes cause a loss of light regardless of the lens used. As for IQ goes, IQ drops slightly because the lens' optical flaws are magnified (i.e softness in the corners, increase in chromatic abberation, etc.).

Canon cameras do not report the exif data regarding the actual f/stop or should I say light transmission. Therefore, with all macro lenses and extension tubes in general, the closer you focus on your subject, the more light is lost as a result.

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OK thanks. This makes sense.

[ebiggs1]

"This makes sense."

Yes both are true.  Remember in photography there is no free lunch.  If you get something, you give up something.